1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, to an apparatus and method of driving data of a liquid crystal display device which can minimize an electromagnetic interference EMI noise by decreasing an output peak current of a data driver.
2. Discussion of the Related Art
Generally, a liquid crystal display device displays images by using the electric and optical properties of liquid crystal. The liquid crystal has the anisotropic property, whereby the liquid crystal is provided with refractive and dielectric indexes changed in long and short axes of liquid crystal molecules. In this respect, alignment of the liquid crystal molecules and the optical property of liquid crystal can be easily controlled. Accordingly, the liquid crystal display device is provided with the alignment direction of liquid crystal molecules being varied based on an electric field applied thereto, so that the liquid crystal display device displays images by controlling the light transmittance.
The liquid crystal display device is comprised of a liquid crystal panel including a plurality of pixels arranged in a matrix configuration; a gate driver for driving gate lines on the liquid crystal panel; and a data driver for driving data lines on the liquid crystal panel.
Each of pixels included in the liquid crystal panel represents a desired color by combining red, green and blue sub-pixels which control the light transmittance according to a data signal. Each of the sub-pixels includes a thin film transistor connected to the gate and data lines; and a liquid crystal capacitor connected to the thin film transistor. In this case, the liquid crystal capacitor charges a differential voltage between the data signal supplied to a pixel electrode through the thin film transistor and a common voltage supplied to a common electrode, and drives the liquid crystal according to the charged differential voltage, to thereby control the light transmittance.
The gate driver drives the gate lines on the Liquid crystal panel in sequence.
Whenever the gate lines are driven respectively, the data driver converts a digital data signal to an analog data signal, and supplies the analog data signal to the data lines on the liquid crystal panel. At this time, as shown in FIG. 1, the data driver simultaneously outputs the data signals Vout corresponding to one horizontal line in response to a source output enable SOE signal. According as the data signals Vout are outputted at the same time, a peak current is generated in that an output current Iout is rapidly raised at an output timing of the data driver.
Due to the high peak current of the data driver, the related art liquid crystal display device has a problem of electromagnetic interference EMI noise. With the increase in size of the liquid crystal display device, an output channel and load of the data driver are increased so that the peak current of data driver is also increased. Accordingly, the EMI noise of broad band BB type is further increased as shown in FIG. 2. Also, the high peak current of data driver causes the increase of power consumption and also causes undesirable effects on the liquid crystal panel, that is, a malfunction of gate line and gate driver.